People enjoy spending time around the water in a variety of ways. Many people swim about and dive to explore the undersea world. Other people spend time on the water's surface, fishing and traveling about in boats and personal watercraft of all shapes and sizes. Still others enjoy activities that combine elements of boating and diver. Several devices have been developed that allow people to pursue these hybrid activities. Many of these devices are designed to be towed behind a boat, thereby allowing a rider to explore a body of water "firsthand," while traveling at an increased rate of speed, over an extended distance.
U.S. Pat. No. 5,558,551 discloses a steerable swimmer towing device that includes a line anchor for attachment to a tow line extending behind a boat. The device is essentially a planar member having handle apertures that allow an individual to engage the device, and a fin extends from the planar member. An individual can manipulate the planar member to steer and dive within the water.
U.S. Pat. No. 5,655,939 discloses a towable board for underwater swimming and for riding on the water surface. The '939 device is planar and includes a pair of wings or panels joined along the central axis of the device. The front of each wing includes a hand-engaging window that allows the device to be gripped by a rider. A rudder-like fin extends from each wing, and a movable bar provides an adjustable connection point to which a tow rope may be attached. The '939 device allows a rider to travel across, and under, water while being towed behind a vehicle.
U.S. Pat. No. 5,605,111 discloses a submersible aquatic sled capable of towing a diver both on the water's surface and below the water's surface. The device includes a tow line attachment for linking to a line pulled by a tow boat. The sled includes handles that allow the device to be steered above and below the water surface by changing the orientation of the plane of the sled. Optional hand shields mounted on the surface of the sled protect the hands of a diver.
Although several towable devices have been developed that allow a swimmer to travel across and below the surface of water, the known devices may be difficult to use for many swimmers. For example, the known devices require that a swimmer have sufficient arm strength sufficient not only to steer the device, but also to maintain a firm grasp of the device while moving. As a result, the known devices are often unusable by children and by many older swimmers, as well.
Even conditioned swimmers may have difficulty controlling the known devices. The known devices essentially provide a towed diving plane behind which a swimmer is pulled. To steer these devices, a rider must attempt to change the orientation of the diving plane with respect to the direction of travel. This is often difficult to accomplish, because the pivot fulcrum is typically the rope attachment point located on the diving plane, itself. As a result, a swimmer must generate large amounts of leverage to overcome the tendency of the device to remain axially aligned with the tow rope. Successful steering of the known device requires large amounts of force, with leverage requirements increasing as tow speed increases. Unfortunately, with these requirements, even strong swimmers find it difficult to control the known devices in a meaningful manner when traveling at increased speeds.
Thus, what is needed is a diver transportation assistance device that includes advantages of the known devices, while addressing the shortcomings they exhibit. The transportation device should support a diver in a prone position, without relying on the diver hand or arm strength. The device should also provide a mechanical advantage that allows a diver to easily produce leverage sufficient to steer the device in a controlled manner at a wide range of speeds. The device should also have pivot fulcrum that is separate from the tow rope attachment point, so that the device will pivot irrespective of tow rope orientation.